Instructional Video6:29
Corbett Maths

Pythagoras Rectangles and Isosceles Triangles

7th - 12th Standards
When does the Pythagorean Theorem come in handy? An intriguing video uses the Pythagorean Theorem to solve problems other than simply finding the length of a side of a right triangle. Pupils find the diagonal of a rectangle and the...
Lesson Plan
Curated OER

Geometry Journal: Isosceles Triangles

10th - 12th
In this isosceles triangles worksheet, students justify and determine the symmetry of an isosceles triangle. They explore the bisector of rectangles. This three-page worksheet contains two problems. Answers are listed on page three.
Assessment
Concord Consortium

Isosceles Triangle Spaces

7th - 10th Standards
How many different types of triangles can your class name? A discovery lesson guides learners through an exploration of the different triangle types and the relationships between their angles and sides. Using coordinate geometry,...
Lesson Plan
Illustrative Mathematics

Lines of Symmetry for Triangles

3rd - 5th Standards
What can symmetry tell us about triangles? After looking at four examples, learners will come to realize that lines of symmetry are different for equilateral, isosceles, and scalene triangles. Use this guided practice activity as an...
Handout
McGraw Hill

Triangles

4th - 7th Standards
After reviewing characteristics of seven types of triangles, young geometers discover how to find the missing angle of a triangle. Then, they practice identifying triangles, find missing angles, and find missing side lengths of...
Lesson Plan
Curated OER

Geometry of Triangles - Week 6

10th - 12th
In this triangle worksheet, young scholars explore the characteristics of triangles. They find the area of a pentagon, lengths of the sides of a triangle and the area of a quadrilateral. This two-page worksheet contains seven problems.
Lesson Plan
Curated OER

Isosceles Triangle Theorem

8th - 9th
In this geometry worksheet, students differentiate between isosceles and regular triangles. They calculate the area and perimeter of the triangle. There are eleven questions with an answer key.
Worksheet
K12 Reader

Classifying Triangles

2nd - 3rd Standards
Bring math and reading informational text together with a reading comprehension lesson. After kids read about isosceles, scalene, and equilateral triangles, they answer five comprehension questions to demonstrate how they can use context...
Lesson Plan
Virginia Department of Education

How Many Triangles?

9th - 11th Standards
Something for young mathematicians to remember: the sum of any two sides must be greater than the third. Class members investigates the Triangle Inequality Theorem to find the relationship between the sides of a triangle. At the...
Assessment
Bowland

Rods and Triangles

6th - 9th
Scholars explore triangles with rods of different lengths. Using rods of 2, 4, 6, 8, and 10 cm class members build as many different types of triangles as they can. They also describe properties of these triangles and determine...
Worksheet
Curated OER

Triangles

10th
In this triangles worksheet, 10th graders solve and complete 22 different problems related to various types of triangles. First, they name the shortest and longest sides and the smallest and largest angles in each of triangles...
Lesson Plan
Curated OER

Study Buddies: Classifying Triangles

4th - 5th
In this math worksheet, students analyze an informative chart about the measurement and angles of equilateral, isosceles and scalene triangles. Students then answer 5 questions about classifying triangles.
Worksheet
Curated OER

Triangles

4th
In this triangles activity, 4th graders study the lengths that are stated for 3 triangles and describe each triangle by its sides. Students describe 3 additional triangles by their angles.
Worksheet
Curated OER

Classify Triangles

4th - 7th
Here is a classifying triangles practice instructional activity in which learners sharpen their problem solving skills as they solve six story problems.
Worksheet
Curated OER

Easy Worksheet: Classify the Triangle

9th - 12th
In this classify the triangle instructional activity, students solve 6 short answer problems. Students identify the type of triangle being described according to its angle measures and side lengths.
Lesson Plan
National Security Agency

Classifying Triangles

4th - 8th Standards
Building on young mathematicians' prior knowledge of three-sided shapes, this instructional activity series explores the defining characteristics of different types of triangles. Starting with a shared reading of the children's...
Lesson Plan
Virginia Department of Education

Special Right Triangles and Right Triangle Trigonometry

9th - 11th Standards
Right triangles are so special! Use special right triangles to discover the trigonometric ratios. Pairs construct special right triangles and find the values of the ratios of the sides. In the process, they discover the ratios stay the...
Worksheet
Curated OER

Congruence of Triangles

10th
In this congruence of triangles activity, 10th graders solve and complete 10 different problems that include measuring the congruence of various triangles. First, they determine the length of a third side of an isosceles triangle. Then,...
Worksheet
Curated OER

Lengths of Horizontal and Vertical Line Segments

5th - 7th
Use this lengths of horizontal and vertical line segments practice worksheet to have learners sharpen their problem solving skills as they solve six story problems.
Worksheet
Curated OER

Triangles

6th - 7th
In this triangle worksheet, students observe pictures of triangles. They name the triangles according to the length of their sides. Twelve right, equilateral and isosceles triangles are provided for identification on this one-page...
Worksheet
Curated OER

Classifying Triangles

8th - 10th
In this classifying triangles learning exercise, students explore given lengths or angle measurements and then classify each triangle as isosceles, scalene or equilateral. They also determine if the triangle may be right, acute or...
Assessment
Inside Mathematics

Circles in Triangles

9th - 12th Standards
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
Handout
Mt. San Antonio Collage

Congruent Triangles Applications

9th - 12th Standards
Triangles are all about threes, and practicing proving postulates is a great way to get started. The first page of the worksheet provides a brief introduction of the different properties and postulates. The remaining pages contain...
Worksheet
Curated OER

Triangles

3rd - 4th
In this triangles worksheet, students identify 3 triangles by the length of their sides and 3 triangles according to their internal angles.